Downhole Cross Flow Prevention During Well and Power Shutdown

ABSTRACT

A system and method for automatically preventing cross flow in a subterranean well during a shutdown event includes a plurality of downhole control valves located within the subterranean well. An energy storage device releases a stored energy during a shutdown event. A primary fail device is a normally close, fail open device that moves to a primary open position during a shutdown event, providing a portion of the stored energy to each of the plurality of downhole control valves during a shutdown event. The portion of the stored energy delivered to each of the plurality of downhole control valves is sufficient to move each of the plurality of downhole control valves to a valve closed position.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

The present disclosure relates in general to the control of subterraneanwells, and more particularly to automatically preventing downholecross-flow of fluids in subterranean multizone intelligent completionwells.

2. Description of the Related Art

The production of oil and gas in multilateral or multizone wellstypically requires the use of various valves and other downholeequipment commonly known as intelligent completions. For example, aninflow control valve (ICV) assembly can be inserted into the well bore,and can include an inflow valve 28 that regulates the flow of fluidthrough the bore. The communication of commands from an operator at thesurface to such valves and other downhole equipment is important toproduction control of the well.

In some current multizone intelligent wells with inflow from multiplezones, only the surface valves and subsurface safety valves are closedduring well shut down. The downhole valves remain open and will havecross flow between zones during the period of shutdown. The downholecontrol valves do not have a mechanism to automatically close and somecurrent auto-close features available for such valves are subject topotential failures. In addition, adding automatic features downhole canbe difficult to install, service, and replace.

During well shutdown, with some currently available systems, because thedownhole valves will remain open, there will be cross flow from higherpressure zone to lower pressure zone through the downhole valve. Thiscrossflow could affect reserves management and ultimately reduce overallrecovery from the well.

SUMMARY OF THE DISCLOSURE

Embodiments of this disclosure provide systems and methods forautomatically shutting down selected downhole control valves withelements that are located at the surface. Features of this disclosurecan be added to the surface system, can be compatible with currentlyavailable intelligent completions, can be used with hydraulic orelectric operated valves The system is operated during power failure orwell shut in. Closing downhole valves will prevent downhole cross flowduring shut in period. In certain embodiments of this disclosure, one ormore of the downhole control valves can remain in an open position andremaining downhole valves closed to allow the well to be producedthrough the open valves at re-start of production so that no excessstart-up operation is required at time of well start up. Once the wellis stable, the closed downhole control valves can be opened in atraditional known manner, such as through supervisory control and dataacquisition (SCADA).

In an embodiment of this disclosure, a system for automaticallypreventing cross flow in a subterranean well during a shutdown eventincludes a plurality of downhole control valves located within thesubterranean well. The system also includes an energy storage device,the energy storage device releasing a stored energy during a shutdownevent. The system further includes a primary fail device, the primaryfail device being a normally close, fail open device that moves to aprimary open position during a shutdown event, providing a portion ofthe stored energy to each of the plurality of downhole control valvesduring a shutdown event. The portion of the stored energy delivered toeach of the plurality of downhole control valves is sufficient to moveeach of the plurality of downhole control valves to a valve closedposition.

In alternate embodiments, the system includes a secondary fail device.The secondary fail device can be a normally open, fail close device thatmoves to a secondary closed position during a shutdown event. Thesecondary fail device can be associated with a one or more of thedownhole control valves and prevent such downhole control valves frommoving to a valve closed position when the portion of the stored energyis provided to each of the plurality of downhole control valves and eachof the other of the plurality of downhole control valves is moved to avalve closed position.

In certain alternate embodiments, the energy storage device can be anaccumulator and the plurality of downhole control valves are hydraulicvalves. Each downhole control valve can be a hydraulically operatedvalve and the secondary fail device can be a valve that is positioned toprevent a pressure media from traveling from the one of the downholecontrol valves when the secondary fail device is in a secondary closedposition. In alternate embodiments, the energy storage device can be anelectric storage device and the plurality of downhole control valves areelectrically activated devices.

In other alternate embodiments, the energy storage device, primary faildevice, and secondary fail device can be located at an earth's surfaceoutside of the subterranean well. Each downhole control valve can beassociated with a separate zone of the subterranean well and in thevalve closed position, each downhole control valve restricts the flow offluids into and out of the separate zone associated with such downholecontrol valve.

In other embodiments of the current disclosure, a system forautomatically preventing cross flow in a subterranean well during ashutdown event includes a plurality of downhole control valves locatedwithin the subterranean well. An accumulator is associated with each ofthe plurality of downhole control valves, the accumulator storing apressure media. The system also includes a primary fail device, theprimary fail device being a valve that moves to a primary open positionduring a shutdown event, releasing a portion of the pressure media tothe close side of each of the plurality of downhole control valvesduring a shutdown event. The system further includes a secondary faildevice, the secondary fail device being a valve that moves to asecondary closed position during a shutdown event. The secondary faildevice is associated with one of the downhole control valves andprevents such one of the downhole control valves from moving to a valveclosed position when the portion of the pressure media is provided toeach of the plurality of downhole control valves and each of the otherof the plurality of downhole control valves is moved to a valve closedposition.

In alternate embodiments, the accumulator, primary fail device, andsecondary fail device can be located at an earth's surface outside ofthe subterranean well. Each downhole control valve can be associatedwith a separate zone of the subterranean well and in the valve closedposition, each downhole control valve can restrict the flow of wellfluids into and out of the separate zone associated with such downholecontrol valve. A control fluid return line can be associated with anopen side of each of the plurality of downhole control valves andprovide a fluid flow path for a trapped pressure control fluid media toexit the open side of the downhole control valve as the downhole controlvalve moves to a valve closed position. The secondary fail device can bepositioned in the surface panel between the open side of the one of thedownhole control valves and the fluid return vent line so that in thesecondary closed position, the secondary fail device prevents thetrapped control fluid pressure media from exiting the open side of theone of the downhole control valves.

In yet other embodiments of the current disclosure, a method forautomatically preventing cross flow in a subterranean well during ashutdown event includes locating a plurality of downhole control valveslocated within the subterranean well. During a shutdown event, a portionof a stored energy is provided to each of the plurality of downholecontrol valves. The portion of the stored energy is sufficient to moveeach of the plurality of downhole control valves to a valve closedposition. The stored energy is released from an energy storage devicewith a primary fail device, the primary fail device being a normallyclose, fail open device that moves to a primary open position during ashutdown event.

In alternate embodiments the method also includes preventing one of theplurality of downhole control valves from moving to a valve closedposition during a shutdown event with a secondary fail device. Thesecondary fail device can be a normally open, fail close deviceassociated with a one or more of the downhole control valves that movesto a secondary closed position during a shutdown event, so that the oneor more of the downhole control valves remains in a valve open positionand each of the other of the plurality of downhole control valves ismoved to a valve closed position.

In certain alternate embodiments, the energy storage device can be anelectric storage device and the plurality of downhole control valves canbe electrically activated devices. In such an embodiment, the step ofreleasing a stored energy from an energy storage device includesreleasing a portion of stored electric energy to each of the pluralityof downhole control valves during a shutdown event. In other alternateembodiments, the energy storage device is an accumulator and the primaryfail device and the secondary fail device are hydraulic valves. In suchembodiments, the step of releasing a stored energy from an energystorage device includes releasing a portion of a pressure media to aclose side of each of the plurality of downhole control valves during ashutdown event.

In yet other alternate embodiments, the method includes providing afluid flow path for a trapped pressure media to exit an open side of thedownhole control valve as the downhole control valve moves to a valveclosed position, with a fluid return line associated with the open sideof each of the plurality of downhole control valves. The secondary faildevice can be positioned between the open side of the downhole controlvalves and the fluid return line, preventing the trapped pressure mediafrom exiting the open side of the downhole control valves with thesecondary fail device when the secondary fail device is in the secondaryclosed position. The energy storage device, primary fail device, andsecondary fail device can be located at earth's surface outside of thesubterranean well. Each downhole control valve can be associated with aseparate zone of the subterranean well so that in the valve closedposition, each downhole control valve restricts the flow of fluids intoand out of the separate zone associated with such downhole controlvalve.

In still other alternate embodiments, fluid from the subterranean wellcan be produced through the one or more of the downhole control valvesduring normal production. After a shutdown event, the primary faildevice can be moved to a primary closed position, and the secondary faildevice can be moved to a secondary open position. At least one of theother of the plurality of downhole control valves can be moved to thevalve open position to restart production from desired zones and theenergy storage device can be recharged.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features, aspects andadvantages of the invention, as well as others that will becomeapparent, are attained and can be understood in detail, a moreparticular description of the invention briefly summarized above may behad by reference to the embodiments thereof that are illustrated in thedrawings that form a part of this specification. It is to be noted,however, that the appended drawings illustrate only preferredembodiments of the invention and are, therefore, not to be consideredlimiting of the invention's scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a schematic section view of a subterranean well with downholecontrol valves in accordance with an embodiment of this disclosure.

FIG. 2 is a schematic diagram of a cross flow prevention system inaccordance with an embodiment of this disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The Specification, which includes the Summary of Disclosure, BriefDescription of the Drawings and the Detailed Description of thePreferred Embodiments, and the appended Claims refer to particularfeatures (including process or method steps) of the invention. Those ofskill in the art understand that the invention includes all possiblecombinations and uses of particular features described in theSpecification. Those of skill in the art understand that the inventionis not limited to or by the description of embodiments given in theSpecification. The inventive subject matter is not restricted exceptonly in the spirit of the Specification and appended Claims.

Those of skill in the art also understand that the terminology used fordescribing particular embodiments does not limit the scope or breadth ofthe invention. In interpreting the Specification and appended Claims,all terms should be interpreted in the broadest possible mannerconsistent with the context of each term. All technical and scientificterms used in the Specification and appended Claims have the samemeaning as commonly understood by one of ordinary skill in the art towhich this invention belongs unless defined otherwise.

As used in the Specification and appended Claims, the singular forms“a”, “an”, and “the” include plural references unless the contextclearly indicates otherwise. As used, the words “comprise,” “has,”“includes”, and all other grammatical variations are each intended tohave an open, non-limiting meaning that does not exclude additionalelements, components or steps. Embodiments of the present invention maysuitably “comprise”, “consist” or “consist essentially of” the limitingfeatures disclosed, and may be practiced in the absence of a limitingfeature not disclosed. For example, it can be recognized by thoseskilled in the art that certain steps can be combined into a singlestep.

Spatial terms describe the relative position of an object or a group ofobjects relative to another object or group of objects. The spatialrelationships apply along vertical and horizontal axes. Orientation andrelational words including “uphole” and “downhole”; “above” and “below”and other like terms are for descriptive convenience and are notlimiting unless otherwise indicated.

Where the Specification or the appended Claims provide a range ofvalues, it is understood that the interval encompasses each interveningvalue between the upper limit and the lower limit as well as the upperlimit and the lower limit. The invention encompasses and bounds smallerranges of the interval subject to any specific exclusion provided.

Where reference is made in the Specification and appended Claims to amethod comprising two or more defined steps, the defined steps can becarried out in any order or simultaneously except where the contextexcludes that possibility. Looking at FIG. 1, subterranean well 10 isshown. Wellhead 12 is located at earth's surface 14 at the opening ofwell 10. Tubing 16 extends a distance into well 10. Well 10 is shown asa multilateral well having a plurality of bores including a main bore18, and a lateral bores 20. In the embodiment shown, tubing 16 is notcemented and does not extend to the first lateral bore 20. Included inat least one of the main bore 18 and one of the lateral bores 20 is aninflow control valve (ICV) assembly 22.

In the example embodiment of FIG. 1, ICV assembly 22 is a device thatregulates the flow of fluid up through well 10 toward wellhead 12. Toaccomplish this, the example ICV assembly 22 has one or more cased holeor open hole packers 24 that substantially seal the hole around the ICVassembly 22, thereby forcing fluid to pass through the ICV control valve28 in order to move to the top of the well 10.

The flow of fluid through the ICV assembly 22 can be regulated bydownhole control valve 28 within the ICV assembly 22. When downholecontrol valve 28 is open, fluid can freely pass through the ICV assembly22. Conversely, when downhole control valve 28 is closed, fluid isrestricted from passing through the ICV assembly 22. The position ofdownhole control valve 28 (valve open, valve closed, or valve partiallyopen) can be controlled by an operator at the earth's surface 14. Bymanipulating the position of downhole control valve 28, the operator cancontrol how much fluid passes through the ICV assembly 22 towards thetop of the well 10. Each downhole control valve 28 can be associatedwith a separate zone or region of well 10 so that when a downholecontrol valve 28 is in the valve closed position, such downhole controlvalve 28 restricts the flow of fluids into and out of the separate zoneassociated with such downhole control valve 28.

In the example embodiment of FIG. 1, downhole control valve 28 is ahydraulically operated valve with an internal piston cavity divided intoclose side 28 a and open side 28 b by piston 28 c. If pressure media isinjected into close side 28 a, downhole control valve 28 will move to avalve closed position. If pressure media is injected into open side 28b, downhole control valve 28 will move to a valve open position. Whenmoving between the valve open and valve closed positions, pressure mediais not only injected into one side 28 b, 28 a of downhole control valve28, but pressure media trapped in the opposite side 28 a, 28 b, mustexit such opposite side 28 a, 28 b in order for piston 28 c to movewithin the piston cavity.

Turning to FIG. 2, cross flow prevention system 30 can include downholecontrol valves 28 and can be used to close some or all of the downholecontrol valves 28 during a shutdown event. A shutdown event can include,for example, an emergency well shutdown, a power failure, an equipmentfailure, or other event that disrupts electrical or other service to thewell systems. Energy storage device 32 can be, for example, anaccumulator charged with a pressurized media. The amount of storedenergy in energy storage device 32 will be enough to operate each of thedownhole control valves 28 and move each of the downhole control valves28 to a valve closed position. Energy storage device 32 can be chargedwith pressure media from fluid reservoir 34. Pump and motor assembly 36can be used to pump pressure media from fluid reservoir 34 to energystorage device 32. After energy storage device 32 has been charged,storage valve 38 can be closed so that pressure media cannot return fromenergy storage device 32 to fluid reservoir 34. Although pressure mediais generally described herein as a hydraulic fluid, other pressurizedliquids or gasses could alternately be utilized.

Cross flow prevention system 30 is shown in the example of FIG. 2 ashaving downhole control valves 28 operated with a pressure media. Inalternate embodiments, downhole control valves 28 can be electricallyoperated valves. Cross flow prevention system can therefore be ahydraulically operated system, an electrically operated system, or acombination of hydraulic and electrically operated system. In alternateembodiments, energy storage device 32 can therefore alternately be anelectrical storage device such as batteries and the batteries can becharged and maintained as part of an open circuit so that the batteriesretain their charge.

Looking at FIG. 2, primary fail device 40 retains the stored energywithin energy storage device 32 when primary fail device 40 is in theprimary closed position. Primary fail device 40 is a normally close,fail open device that moves to a primary open position during a shutdownevent. When primary fail device 40 moves to a primary open position, thestored energy is released. A portion of the stored energy is deliveredto each of the plurality of downhole control valves 28. The portion ofthe stored energy delivered to each of the downhole control valves 28during a shutdown event is sufficient to move each of the plurality ofdownhole control valves 28 to a valve closed position.

In the example of FIG. 2, pressure media stored within energy storagedevice 32 is delivered to close side 28 a of each of the plurality ofdownhole control valves 28 during a shutdown event. Pressure media willbe delivered through close delivery line 42. Which is the line to closeall the downhole valves Pressure media can pass through one way valve 44and close line valve 46, which are located along close delivery line 42between energy storage device 32 and downhole control valves 28.

As pressure media is delivered to close side 28 a of each of theplurality of downhole control valves 28, an open line 58 associated withopen side 28 b of each of the plurality of downhole control valves 28will provide a fluid flow path for trapped pressure media within openside 28 b to exit open side 28 b as the downhole control valve 28 movesto a valve closed position. The trapped pressure media will return tofluid reservoir 34.

In an alternate embodiment, primary fail device 40 can be a gate thatcloses to allow power stored within batteries of energy storage device32 to be delivered to electrically operated downhole control valves 28.

Looking at the example embodiment of FIG. 2, cross flow preventionsystem 30 can also include at least one secondary fail device 50.Secondary fail device 50 is a normally open, fail close device. During ashutdown event, the secondary fail device 50 moves to a secondary closedposition. One of the secondary fail devices 50 can be associated withone or more of the downhole control valves 28 and can be located betweenthe open side 28 b and the return line 48 so that in the secondaryclosed position, the secondary fail device 50 prevents the trappedpressure media in the open side 28 b from exiting the open side 28 b ofthe downhole control valve 28. Because the trapped pressure cannot exitthe open side 28 b, piston 28 c cannot move and such downhole controlvalve 28 will be prevented from moving to a valve closed position, evenwhen pressure media is being supplied to close side 28 a of downholecontrol valve 28.

In alternate embodiments, secondary fail device 50 can be a gate that ispart of an electrical operated valve system. During a shutdown event,the gate of secondary fail device 50 will open, causing the circuitassociated with one of the downhole control valves 28 to be incompleteso that such downhole control valve 28 cannot be signaled to move to theclosed position.

Looking at both FIGS. 1 and 2, energy storage device 32, primary faildevice 40, and each secondary fail device 50 are located at an earth'ssurface 14 outside of the subterranean well 10 and can be part ofsurface control panel 52. Connector line 54 can extend from surfacecontrol panel 52, down well 10, to downhole control valves 28. Connectorline 54 can include, for example, a portion of close delivery line 42and open line 58. Connector line 54 as well as the downhole controlvalves and associated ICV assemblies 22 can be standard or pre-existingequipment. Therefore in order to include cross flow prevention system30, an operator would only need to add elements located at the earth'ssurface 14 and would not have to make changes or install additionalcomponents downhole.

In an example of operation, in order to produce fluids from well 10through ICV assemblies 22, an operator can open downhole control valves28. To open downhole control valves 28, pressure media can be pumpedfrom fluid reservoir 34 with pump and motor assembly 36 to open side 28b of downhole control valves 28. Pressure media can be pumped throughopen control valves 56 to open lines 58 to reach open side 28 b ofdownhole control valves 28. This moves the piston in the ICV 28 in theopen direction and pushes the control fluid to surface through closeline 42. This control fluid is vented to the tank through devices 50 andline 48. Valve 46 in closed position stops this fluid from going to thepump line. Open control valves 56 can be normally closed valves that arekept in a closed position during normal operations and opened whendownhole control valves 28 are to be moved to a valve open position.When pumping pressure media to open side 28 b of downhole control valves28, close line valve 46, which is normally open, can be closed so thatclose delivery line 42 is blocked and pressure media from the pump 36will not reach close side 28 a of downhole control valves 28 during theoperation to open the ICVs 28. Return line valve 60, which is normallyopen, will be closed while pumping pressure media to open side 28 b ofdownhole control valves 28 so that pressure media being used to fillopen side 28 b will not instead return through return line valve 60 tofluid reservoir 34. Device 50 in line 58 will be in the closed positionwhile opening the downhole valves 28.

As downhole control valves 28 are opening, pressure media trapped inclose side 28 a of downhole control valves 28 can exit close side 28 aand return to fluid reservoir 34 by way of one of the secondary faildevices 50 and return line 48. During normal operating conditions,secondary fail devices 50 are in a secondary open position. During theoperation to open the ICVs 28, it is acceptable for the fluid in closeside 28 a to flow through close delivery line 42 and secondary faildevice 50, return line 48 to reach the fluid reservoir 34.

After downhole control valves 28 are opened, close line valve 46 can bereturned to its normal open position, open control valves 56 can bereturned to their normal closed positions, and return line valve 60 canbe returned to its normal open position. Secondary fail device 50 willbe brought to an open position. A number of pressure gauges 62 can beused to monitor the pressure within varies flow lines of the cross flowprevention system 30. During normal operating conditions, energy storagedevice 32 is charged and primary fail device 40 is in a closed position.Fluids can be produced from well 10 from a number of zones through ICVassemblies 22.

During a shutdown event, the power or force retaining primary faildevice 40 in a primary closed position will be cut off and primary faildevice 40 will move to a primary open position. Device 50 in line 42will also move from a primary open position to close position. This willallow the stored energy of energy storage device 32 to be released andbe delivered to close side 28 a of each downhole control valve 28. Suchenergy will be sufficient to move downhole control valves 28 to thevalve closed position. The control fluid displaced from the valvesduring the closing operation will return to surface through controllines 58.

In certain embodiments, no secondary fail device 50 is included in thereturn lines 58 that will block the path of pressure media returning tofluid reservoir 34. In such an embodiment, all of the downhole controlvalves 28 will move to a valve closed position and production of fluidsfrom, and injection of fluids into, all zones of well 10 will bestopped.

In the example embodiment of FIG. 2, one or more of the plurality ofdownhole control valves 28 is prevented from moving to a valve closedposition during a shutdown event with a secondary fail device 50 in thereturn line 58. Secondary fail device 50 in line 58 will move fromprimary open to closed position during power shutdown. This blocks thefluid flow path to the return line 48 for the trapped pressure media inopen side 28 b so that the pressure media in open side 28 b cannot exitthe downhole control valve 28. In such an embodiment, the downholecontrol valve 28 associated with the secondary fail devices 50 incontrol line 58 will remain in the open position while downhole valvesassociated with return line valve 60 will move to the closed position.

After the shutdown event, in order to resume normal operation of well10, primary fail device 40 can be returned to the primary closedposition. Secondary fail devices 50 can be returned to the secondaryopen position. During well start up well 10 can continue to be producedfrom the open zones that is associated with the downhole control valve28 that is in the valve open position. This will expedite the start ofproduction after shut down by reducing the number of steps required toreturn the well 10 to normal operating conditions. Once the flow isstable, the other zones can be remotely opened by moving at least one ofthe downhole control valves 28 to the valve open position, and thedownhole control valves 28 can otherwise be opened and closed as deemedappropriate by the operator. Energy storage device 32 can be rechargedand cross flow prevention system 30 is then ready to operate during asubsequent shutdown event.

Embodiments described herein, therefore, are well adapted to carry outthe objects and attain the ends and advantages mentioned, as well asothers inherent therein. While a presently preferred embodiment has beengiven for purposes of disclosure, numerous changes exist in the detailsof procedures for accomplishing the desired results. These and othersimilar modifications will readily suggest themselves to those skilledin the art, and are intended to be encompassed within the spirit of thepresent invention disclosed herein and the scope of the appended claims.

Therefore as described herein, during operation, surface control panel52 has three distinct operating conditions. In a first operatingcondition, normal well production is undertaken with multiple downholecontrol valves 28 in the open position. Accumulator 32 is charged,primary fail device 40 is closed, and all secondary fail devices 50 arein an open position. This is a waiting period with no valves moving andthe system is waiting for a trigger to close one or more downholecontrol valves 28.

In a second operating condition, a trigger such as, for example, a powerfailure, to close one or more downhole control valves occurs. As aresult of the trigger, primary fail device 40 is open and secondary faildevices 50 are closed. Pressure is applied through the close deliveryline 42. This causes the selected downhole valves 28 that are associatedwith open return line valves 60 to close to and selected downholecontrol valves 28 that are associated with secondary fail devices 50,which are in a closed position, to remain open.

In a third operating condition, the opening of downhole control valves28 through providing pressure through open control valves 56 and openlines 58 is undertaken. Close line valve 46 and return line valve 60 areclosed. Secondary fail device 50 associated with open line 58 will beclosed while secondary fail device 50 associated with close deliveryline 42 will be in an open position

What is claimed is:
 1. A system for automatically preventing cross flowin a subterranean well during a shutdown event, the system comprising: aplurality of downhole control valves located within the subterraneanwell; an energy storage device, the energy storage device releasing astored energy during the shutdown event; and a primary fail device, theprimary fail device being a normally close, fail open device that movesto a primary open position during the shutdown event, providing aportion of the stored energy to each of the plurality of downholecontrol valves during the shutdown event, the portion of the storedenergy delivered to each of the plurality of downhole control valvesbeing sufficient to move each of the plurality of downhole controlvalves to a valve closed position.
 2. A system in accordance with claim1, further comprising a secondary fail device, the secondary fail devicebeing a normally open, fail close device that moves to a secondaryclosed position during the shutdown event, the secondary fail devicebeing associated with a one of the downhole control valves andpreventing such one of the downhole control valves from moving to thevalve closed position when the portion of the stored energy is providedto each of the plurality of downhole control valves and each of theother of the plurality of downhole control valves is moved to the valveclosed position.
 3. A system in accordance with claim 2, wherein theenergy storage device is an accumulator and the plurality of downholecontrol valves are hydraulic valves.
 4. A system in accordance withclaim 2, wherein the energy storage device is an electric storage deviceand the plurality of downhole control valves are electrically activateddevices.
 5. A system in accordance with claim 2, wherein the energystorage device, primary fail device, and secondary fail device arelocated at an earth's surface outside of the subterranean well.
 6. Asystem in accordance with claim 2, wherein each downhole control valveis a hydraulically operated valve and the secondary fail device is avalve that is positioned to prevent a pressure media from traveling fromthe one of the downhole control valves when the secondary fail device isin the secondary closed position.
 7. A system in accordance with claim1, wherein each downhole control valve is associated with a separatezone of the subterranean well and in the valve closed position, eachdownhole control valve restricts a flow of fluids into and out of theseparate zone associated with such downhole control valve.
 8. A systemfor automatically preventing cross flow in a subterranean well during ashutdown event, the system comprising: a plurality of downhole controlvalves located within the subterranean well; an accumulator associatedwith each of the plurality of downhole control valves, the accumulatorstoring a pressure media; a primary fail device, the primary fail devicebeing a valve that moves to a primary open position during the shutdownevent, releasing a portion of the pressure media to the close side ofeach of the plurality of downhole control valves during the shutdownevent; and a secondary fail device, the secondary fail device being avalve that moves to a secondary closed position during the shutdownevent, the secondary fail device being associated with one of thedownhole control valves and preventing such one of the downhole controlvalves from moving to a valve closed position when the portion of thepressure media is provided to each of the plurality of downhole controlvalves and each of the other of the plurality of downhole control valvesis moved to the valve closed position.
 9. A system in accordance withclaim 8, wherein the accumulator, primary fail device, and secondaryfail device are located at an earth's surface outside of thesubterranean well.
 10. A system in accordance with claim 8, wherein eachdownhole control valve is associated with a separate zone of thesubterranean well and in the valve closed position, each downholecontrol valve restricts a flow of fluids into and out of the separatezone associated with such downhole control valve.
 11. A system inaccordance with claim 8, further comprising a fluid return lineassociated with an open side of each of the plurality of downholecontrol valves and providing a fluid flow path for a trapped pressuremedia to exit the open side of the downhole control valve as thedownhole control valve moves to the valve closed position.
 12. A systemin accordance with claim 11, wherein the secondary fail device ispositioned between the open side of the one of the downhole controlvalves and the fluid return line so that in the secondary closedposition, the secondary fail device prevents the trapped pressure mediafrom exiting the open side of the one of the downhole control valves.13. A method for automatically preventing cross flow in a subterraneanwell during a shutdown event, the method comprising: locating aplurality of downhole control valves located within the subterraneanwell; and during the shutdown event, providing a portion of a storedenergy to each of the plurality of downhole control valves, the portionof the stored energy being sufficient to move each of the plurality ofdownhole control valves to a valve closed position, the stored energybeing released from an energy storage device with a primary fail device,the primary fail device being a normally close, fail open device thatmoves to a primary open position during the shutdown event.
 14. A methodin accordance with claim 13, further comprising preventing one of theplurality of downhole control valves from moving to the valve closedposition during the shutdown event with a secondary fail device, thesecondary fail device being a normally open, fail close deviceassociated with a one of the downhole control valves that moves to asecondary closed position during the shutdown event, so that the one ofthe downhole control valves remains in a valve open position and each ofthe other of the plurality of downhole control valves is moved to thevalve closed position.
 15. A method in accordance with claim 14, whereinthe energy storage device is an electric storage device and theplurality of downhole control valves are electrically activated devices,and wherein the step of releasing the stored energy from the energystorage device includes releasing a portion of stored electric energy toeach of the plurality of downhole control valves during the shutdownevent.
 16. A method in accordance with claim 14, wherein the energystorage device is an accumulator and the primary fail device and thesecondary fail device are hydraulic valves, and wherein the step ofreleasing the stored energy from the energy storage device includesreleasing the portion of a pressure media to a close side of each of theplurality of downhole control valves during the shutdown event.
 17. Amethod in accordance with claim 14, further comprising providing a fluidflow path for a trapped pressure media to exit an open side of thedownhole control valve as the downhole control valve moves to the valveclosed position with a fluid return line associated with the open sideof each of the plurality of downhole control valves.
 18. A method inaccordance with claim 17, wherein the secondary fail device ispositioned between the open side of the one of the downhole controlvalves and the fluid return line, the method further comprisingpreventing the trapped pressure media from exiting the open side of theone of the downhole control valves with the secondary fail device whenthe secondary fail device is in the secondary closed position.
 19. Amethod in accordance with claim 14, further comprising locating theenergy storage device, primary fail device, and secondary fail device atan earth's surface outside of the subterranean well.
 20. A method inaccordance with claim 14, further comprising after the shutdown event:moving the primary fail device to a primary closed position; moving thesecondary fail device to a secondary open position; moving at least oneof the other of the plurality of downhole control valves to the valveopen position; and recharging the energy storage device.
 21. A method inaccordance with claim 13, further comprising associating each downholecontrol valve with a separate zone of the subterranean well so that inthe valve closed position, each downhole control valve restricts a flowof fluids into and out of the separate zone associated with suchdownhole control valve.